[1.3.1] Ferram Aerospace Research: v0.15.9.1 "Liepmann" 4/2/18

[cartographer]

Bug/Crash report here.

Image: http://i.imgur.com/55Zhc7x.jpg

Log: http://s000.tinyupload.com/index.php?file_id=63537421523359981502

Mods installed are FAR, Kethane, B9, and Part Catalog (but its pretty obvious that its from to FAR). Long and short of it is that the static AoA sweeper-thing crashes KSP if you set the view range upper bound to 90 when analyzing a craft that has the center of lift much farther behind the center of mass (or so it appears). Easiest way to recreate would be just stick some wings on the back of two orange tanks in the SPH. The lines in the analyzer also split and do some crazy things before 90 (reminds me of the sort of splitting/chaos you see in nonlinear diff. equations, which makes sense in hindsight, given the whole aerodynamics thing).

[wased89]

I've had problems with the red drag lines in the popup window being too high whenever I put items inside a cargo bay door from B9 Aerospace, even though the parts are shielded, they still produce drag. Why is that??

[Autochton]

Does anyone have any advice for calculating aerobreaking altitudes when using FAR?

Thanks

Make it so your ship can vary its drag. That way, you can enter the atmosphere at higher drag, slow down to a little above your desired target velocity, go to low drag, and not lose much velocity coming through the remaining atmosphere. I usually manage my reentry that way (although c.f. my above trouble keeping my spaceplanes properly oriented for high drag, and the advice for it...) and it should work well for aerocapture too.

Basically, you have two ways to manage drag: Attitude and shape. If you create a craft that is streamlined one way but not another (like a plane, not so streamlined with the belly straight into the wind) you can simply use your attitude to regulate your drag. Be mindful of aerodynamic stability, stall angles, etc. though, those will affect what attitudes you can hold. If you have some geometry altering mod available (Infernal Robotics or TT MultiWheels contain such capability, and some parts packs like B9 have effective air brake parts) , you can set your ship geometry to high drag for the braking, staying mindful of what that will do to your center of drag - if it moves ahead of your center of mass, you are having a bad problem and will not be going (back) to space today (iow, your ship will flip out and kill everyone).

[ferram4]

@nhnifong: Currently no, but I can set up a mediafire folder for that purpose.

@cartographer: That is a known issue that I am looking into.

@wased89: That is also a known issue, though I'm not sure what the cause is.

[asmi]

Hello ferram! Just encountered an issue - it looks like the module is applied twice. Screenshot: http://www.asmitech.com/Stuff/KSP/FAR_DOUBLE_MODULE.png log file: http://www.asmitech.com/Stuff/KSP/FAR_DOUBLE_MODULE.LOG.txt

[ferram4]

That is simply due to the FARControlSys class (the module that creates the FAR flight GUI) and the FARBasicDragModel class (the module that applies drag) inheriting from the same base class (FAR BaseAerodynamics) that has a bunch of necessary and useful aerodynamic values (such as cl, cd, cm).

[asmi]

That is simply due to the FARControlSys class (the module that creates the FAR flight GUI) and the FARBasicDragModel class (the module that applies drag) inheriting from the same base class (FAR BaseAerodynamics) that has a bunch of necessary and useful aerodynamic values (such as cl, cd, cm).

But why are the values different? I've neves seen anything like that before...

[ferram4]

Basically, the FARControlSys cl, cd, and cm are the values that would appear in the FlightData GUI. The FARBasicDragModel cl, cd and cm are used to apply forces to the part.

[asmi]

Basically, the FARControlSys cl, cd, and cm are the values that would appear in the FlightData GUI. The FARBasicDragModel cl, cd and cm are used to apply forces to the part.

Got it! Thanks!

[Kalista]

I'm having a slight problem with the mod on the right click window Ferram's is adding so much information that its making the buttons to control some fuctions on command pods unclickible. I was wondering where I would go to have those stop showing up on those menus since i also use ioncross crew support not being able to turn on my CO2 scrubber is making the game nearly impossible here is a screenshot with the text id like to not show up on the menu circled http://cloud-2.steampowered.com/ugc/903255624207946805/AD1B5A6C4D1FC59E34A8AB41541DEFF775A3A90E/

[jrandom]

If you hold down your middle mouse button, you can pan the screen around. This is how I've been getting to my IonCross controls when the menu is too long. ('Tis a workaround and we definitely need a different spot for those FAR numbers to show up.)

[AppleJacks69]

I'm pretty sure I installed it correctly because some other mods are installed the same but the new physics don't work. Everything seems the same really...

[rosenkranz]

ferram4, just wanted to say that i'm enjoying the bejeezus out of this mod but I've got a question.

Given that stock you need 4500 dV to get to orbit, why does FAR let you get up in 3500 dV or less? Is that just a natural result from your simulation at stated Kerbin atmo densities or did you tune it to that?

Reason I'm asking is because as much as I enjoy being able to get to orbit in 3500 dV, it makes it almost ridiculously easy to get small rockets to orbit. Even larger payloads are pretty darn easy to lift. I was able to get a 125t payload into orbit on a 494t rocket which is a payload ratio of over 25%.

I suppose my question is there a way to tune this up to make the dV requirement to orbit closer to stock but still keep the much better aerodynamic behavior your mod gives us? Kind of a 'harder' mode if you will.

Any thoughts on this?

[Van Disaster]

You use less dV because you've got all the dV you spend in stock overcoming drag losses back all of a sudden ( which is realistic - Earth rockets lose 1-200 generally, I think Saturn V losses were about 40m/s ), there's nothing else going on. Parts are tuned for stock aero, mebbe we need FAR nerfs for rocket engines like the jets have been.

[p1t1o]

You use less dV because you've got all the dV you spend in stock overcoming drag losses back all of a sudden ( which is realistic - Earth rockets lose 1-200 generally, I think Saturn V losses were about 40m/s ), there's nothing else going on. Parts are tuned for stock aero, mebbe we need FAR nerfs for rocket engines like the jets have been.

Simplest way would be to increase Kerbin's gravity, or increase the depth of its atmosphere, or both, so you wouldn't have to make changes to every engine, some of which would get missed.

Not that I think its too easy to get to orbit, besides, playing with MissionController, the challenge is to build the cheapest rocket for a given payload/mission as opposed to "how much mass can I orbit in one go".

[ferram4]

@AppleJacks69: Does right-clicking on a part bring up a bunch of new flags, like "isShielded", "cl", "cd", "cm", etc? For wings, is there also a "Stall" flag in the right-click menu? Does a GUI show up in the editor and flight scenes? If not, you haven't installed it correctly. Make sure that the FerramAerospaceResearch folder is in the GameData folder and that ModuleManager.dll is located in the GameData root. Installing the dlls in the old Plugins folder will cause problems.

Other than that, make sure you're actually putting nose cones on your rockets and taking steps to streamline your vehicles. If you're still trying to launch bricks, don't be surprised when they fly like bricks.

@rosenkranz: In KSP you only need ~2.2 km/s to stay in orbit at ~85km. That means that the remaining ~2.3 km/s needed for a stock launch is divided among gravity and drag loses, spread about evenly; this makes for ~1 km/s lost to gravity and drag each. With the drag reduced to realistic levels for aerodynamic vehicles, that 1 km/s drops away.

Now, none of these numbers have any dependency on the actual parts used (well, except for the drag loses); with FAR it will always take less dV to get to orbit than in stock, so long as stock has its crazy-large drag. The only way to increase the dV to orbit is one of these three solutions:

1. Increase the size of Kerbin and scale up its gravity; this solution has been rejected by the devs numerous times due to the memory requirements for that large a planetary surface.
   
2. Increase the scale height of Kerbin's atmosphere and set the cut-off limit higher to increase gravity and drag losses; the problem is that atmospheres in KSP are already much taller relative to their planet's orbital radius than in real life. The much higher orbits needed to get out of the atmosphere will also make the planets look smaller, a frequent enough complaint already.
   
3. Increase the drag that FAR applies; this would sacrifice a fair bit of realism for the sole purpose of increasing the difficulty. In general, not something I want to do, especially since the difficulty of launching something highly complex with FAR installed is already an exercise in "how do I fit this into a fairing / on top of a rocket?"
   

What I think you're actually asking for is a nerf to the Isp of the engines we have to try and push the payload ratios lower, despite the lower dV requirements. The problem is that I'm not really in the mood to attempt a serious engine re-balancing attempt, particularly when every update causes the drag of vehicles to change and I'd have to balance with that in mind as well. If someone else wants to try running that type of a part.cfg mod with ModuleManager support, I'd be happy to send FAR users over to try it, but I really don't want to take on that extra responsibility myself.

[rosenkranz]

Wow, that was a quick and comprehensive response. Much appreciated. I don't understand all the mechanics so I had to ask.

I suspect when Squad does get around to replacing the placeholder aerodynamics model they're going to make the same observation and was wondering how they might go about balancing the system for gameplay purposes.

[rosenkranz]

Simplest way would be to increase Kerbin's gravity, or increase the depth of its atmosphere, or both, so you wouldn't have to make changes to every engine, some of which would get missed.

Not that I think its too easy to get to orbit, besides, playing with MissionController, the challenge is to build the cheapest rocket for a given payload/mission as opposed to "how much mass can I orbit in one go".

Playing missioncontroller is why I made this observation. I've blown through most of the missions with reative ease. First rocket you make is less that 6,000k with a 50,000k payout. The most expensive rocket i've had to make so far was only 23,000k for a 95,000k payout.

Now none of this is has anything to do with FAR. I was just curious. Of course i've not tried to play missoncontrol without FAR, so i'm not entirely sure if that wouldn't have been even easier. I dunno, i've been playing KSP since .18 and have a pretty good handle on the mechanics.

One thing i've noticed is that stock it's harder to get things up but easier to get things down. With FAR, it's easier to get things up and a heck of a lot harder to get them back down without going splat. DRE makes it even harder to get things back down.

[taniwha]

rosenkranz: sounds like rather than nerfing anything with FAR, missioncontroller should be adjusted (in budget and payoffs) for FAR.

Also, while getting small rockets up is easy/cheap, getting big stuff up is not. FAR is very unforgiving towards poor rocket design, and sometimes even towards designs that look ok (due to the hidden center of drag).

I suspect that if Squad ever puts in semi-realistic aerodynamics, they'll just shrug their shoulders at the delta-v difference.

[NathanKell]

Judging by the number of people who come in here to complain that rockets are unflyable with FAR, maybe we should leave the payouts that high to account for many tries.

[wased89]

@ferram About my problem with the batteries creating drag in cargo bays. Could the drag be possibly influenced by the mass?

[GrizzlyJones]

I was wondering if there's a way to get the part of the mod that lets you set individual control surfaces for specific axis, and thats all I'm looking for at the moment. Maybe if you were to release it seperately from FAR, there would be numerous people to appreciate it. I know I've seen numerous people looking, and maybe like me aren't looking for the full mod (no disrespect, I've used it before, just not feeling it right now)

[NathanKell]

Speaking of control surfaces, ferram, a ways back someone suggested (before I got around to suggesting!) adding control surface activate/deactivate to right-click / actiongroups. This would be massively useful for craft that reenter the atmosphere retrograde, since otherwise control surfaces will deflect the wrong way. Crossrange capability is real hard to get, without borknig control on the way up!

The plan: add a second set of control surfaces and set their deflection negative. If you can't disable them, they'll fight the other surfaces. If you can, though, you can enable them on deorbit and disable main ones, and have great controllability.

[taniwha]

NathanKell: heh, probably.

[Van Disaster]

Adding that mod that fixed the way ISP works might also balance things - iirc that will start your engines rather nerfed as far as thrust goes & progressively un-nerf them as you get higher. I haven't tried it yet personally, I can't add much to my install before it gets unstable and I don't know what it does to jets, but it does sound like something that should go hand in hand.